Generally, a liquid crystal display device having such features as a light weight, a thin shape, and low power consumption is used as a display device. The liquid crystal display device is equipped with an array substrate, a counter substrate arranged opposing the array substrate, and a liquid crystal layer held between the array substrate and the counter substrate.
The array substrate includes a glass substrate. On the glass substrate, a plurality of signal lines and scanning lines are arranged crossing each other in a display region. A TFT (Thin Film Transistor) which constitutes a pixel is arranged near an intersection of each signal line and each scanning line. Moreover, a driver circuit connected to the plurality of scanning lines is provided on the glass substrate.
When the TFT is formed using poly-silicon, the driver circuit can be formed simultaneously with the TFT using the poly-silicon. Furthermore, it is not necessary to lay out the scanning lines on a frame region of the glass substrate. Therefore, in the liquid crystal display device with the TFT formed of the poly-silicon, the frame region hardly expands even if the number of pixels of the liquid crystal display device increases.
By the way, the screen size of the liquid crystal display device becomes large for a cell phone unit use, and the number of pixels tends to increase every year. Since an occupancy area of the driver circuit for each scanning line is decided, when the number of pixels increases and a pixel pitch becomes narrow, the lay-out width of the driver circuit with respect to the pixel pitch expands relatively. However, since portability is requested in the cell phone unit, the cell phone unit has a problem that the lateral width of the substrate cannot be increased.
Then, it is thought to arrange the above-mentioned driver circuit by dividing into two or three driver circuits on the both sides of the screen. However, it is necessary to provide mutually different synchronization signals to the respective driver circuits in this case. However, since it is difficult to generate two or three kinds of synchronization signals in the conventional driver circuit, it is necessary to newly develop the driver circuit (integrated circuit) which can generate two or three kinds of synchronization signals, and as a consequence, which causes the raising of a manufacturing cost, and further, the raising of a product price.